Field of the Invention
The present invention relates to a manipulator for medical use, and particularly to a manipulator for medical use having a tip tool including a rolling mechanism rotatable about an axis which is directed to a distal end thereof.
Description of the Related Art
When surgery is traditionally performed, there is a long incision made so the surgeon can view and repair the internal parts of the patient. The long incision site can be a significant concern because it is subject to infection and is often the most traumatic and painful part of the patient's recovery. In recent years, many surgeons have been using endoscopic tools and performing minimally invasive surgery, thereby vastly reducing the size of the incision.
A manipulator system is composed of a manipulator body and a controller therefor, as described in Japanese Laid-Open Patent Publication No. 2004-105451, for example. The manipulator body contains an operating unit controlled by human and a working unit interchangeably removable from the operating unit.
The working unit (or an instrument) has a slender connecting shaft and an end working portion (also referred to as an end effector) disposed at the distal end of the connecting shaft. An actuator (a motor) for driving the end working portion via a wire is disposed in the operating unit. The wire is wound around a pulley in the vicinity of the proximal end. The motor in the operating unit is driven by the controller, whereby the wire is moved via the pulley.
The working unit is detachable from the operating unit, in order to easily carry out washing and the like after an operation. The working unit may be a gripper, a scissor, an electric surgical knife, an ultrasonic surgical knife, a medical drill, or the like, and may be selected depending on a procedure in a laparoscopic operation. In order to change the above working units, the working unit is preferably removable from the operating unit.
In the working unit, the pulley at the proximal end is engaged with a rotary shaft of the motor in the operating unit.
Robotic tools have been developed to further improve the minimally invasive surgical process. These tools are highly specialized. They must perform the function that a surgeon would perform in a miniaturized manner. Surgeons perform many different functions on internal organs such as cutting, scraping, and suturing.
Many of these functions require rotation of the tool in a similar manner to how the surgeon would rotate his wrist during traditional surgery. Specifically, when a tip tool has a rolling mechanism which rotates about an axis directed to a distal end thereof, a suturing operation or the like can be easily and suitably performed without the need for an operator to rotate his wrist. It is preferable that the rolling mechanism rotates in a certain rotational angular range, for example, a range of 360° or more.
The tip tool is imaged by an endoscope and displayed on a monitor. However, a gripper portion at the tip end is not necessarily imaged clearly. Also, since the gripper portion is often vertically symmetric, when the gripper portion is rotated 180°, the amount of rotation in such a gripper portion may be difficult to visually confirm.
Thus, there is a need for a device and a method for easily and reliably identifying the amount of rotation of the tool tip of a minimally invasive robotic surgical device.